Why are sharks so awesome? TEDEd

The rete mirabile is a:

• Nerve bundle that helps the muscles, gut and brain of some sharks stay warm

• Nerve bundle that helps the muscles, gut and brain of some sharks stay warm

• Group of tendons involved in fast swimming and prey detection

• A bundle of blood vessels where blood flowing in opposite directions transfers heat from warm vessels to cool ones

How many shark species are in existence today?

• 25

• 67

• 100-200

• 400-500

• 1000+

How many shark species are threatened?

• All shark species are threatened

• One-third

• None

Which set of traits is not found in sharks?

• Ampullae of Lorenzini, tough skin to which muscles attach, large oily livers

• Streamlined bodies, dermal denticles and tapeta lucida

• Multiple teeth rows, rete mirabile, countershading

• Swim bladders, bony skeletons and highly maneuverable fins

• Fluoride-coated teeth, moveable jaws, warm bloodedness

When did sharks appear in the ocean?

• Shortly after the big dinosaurs went extinct

• 200-300 million years ago

• 400 million years ago

• Half a billion years ago

• 4 x 10^5 years ago

A shark’s skeleton is made from the same skeletal material in your:

• Spinal cord

• Nose

• Femur

• Digestive tract

• Toenails

Which statement is false?

• A shark has tiny tooth-like structures on its skin called dermal denticles that interact with the water to slow it down

• Shark trunk muscles attach directly to its skin and help transfer muscular contractions to the tail

• In addition to having a keen sense of smell, sharks can also sense electrical signals from their prey

• Sharks have flexible bodies made of cartilage, which is lighter than bone

• The teeth of a shark can tell you what type of prey it likely eats